An efficient model for calculating vibration in buildings on pile-foundations from underground railway trains Seminar

Vibration from underground railways has a significant environmental impact on nearby buildings and their occupants. Vibration is generated at the wheel-rail interface and propagates to nearby buildings where it causes vibration of walls and floors. Vibration of buildings can cause annoyance to occupants and malfunctioning of sensitive equipment. Vibration of walls and floors is also reradiated as noise which may result in a serious problem especially in sensitive buildings such as concert halls and recording studios.

This presentation introduces a newly developed fast running model for the calculation of vibration in a building on pile-foundation due to moving trains in a nearby underground tunnel. The model is three-dimensional and it calculates the Power Spectral Density (PSD) of the building’s responses due to trains moving on floating-slab tracks with random roughness. The tunnel and its surrounding soil are modelled as a cylindrical shell embedded in half-space using the well-known PiP model. The building and its piles are modelled as a 2D frame using the dynamic stiffness matrix. Coupling between the foundation and the ground is performed using the theory of joining subsystems in the frequency domain. The latter requires calculations of transfer functions of a half-space model. A convenient choice based on the thin-layer method is selected in this work for the calculations of responses in a half-space due to circular strip loadings. The coupling considers the influence of the building’s dynamics on the incident wave field from the tunnel, but ignores any reflections of building’s waves from the tunnel.

The presentation shows predictions of vibration for a building at its piles and at points within its floors. Comparisons are shown between vibration of the ground before and after the coupling of building. It is concluded from the comparison that the dynamics of the building and its foundation significantly change the incident vibration field from the tunnel.